I need to start the PWM from 4ms to 10ms and I did it with IF statement but nothing happend

so could any one help me

and one last thing the code that I wrote is

for (t;t<0.022; t=t+0.001)

{

if ( (t>0.004) &&(t<0.011) )

{

aPin1 = (HIGH);

analogWrite (aPin1 ,123);

}

else {

aPin1 = (LOW);

}

if ( (t>0.014) && (t<0.021) )

{

bPin2 = (HIGH);

analogWrite (bPin2 ,123);

}

else {

bPin2 =(LOW);

}

if ( t = 0.021)

{

t = 0 ;

}